The Hollow Clock has no face, just an open space with an hour and minute hand that move as expected. Only the longer minute hand has any apparent connection to the rest of the clock body ...

The Hollow Clock has no face, just an open space with an hour and minute hand that move as expected. Only the longer minute hand has any apparent connection to the rest of the clock body ...

On this clock above the minute hand is pointing to 12 so it is o'clock. The hour hand points to 3. It is 3 o'clock. On this clock, the minute hand points to 6 so it is ‘half-past’.

The hands of a clock coincide 22 times in 24 hours, or 11 times in each 12-hour period. While it seems they meet every hour, the actual timing is slightly more complex. Tap to read in detail.

On this clock above the minute hand is pointing to 12 so it is o'clock. The hour hand points to 3. It is 3 o'clock. On this clock, the minute hand points to 6 so it is ‘half-past’.

The minute hand on the Doomsday Clock is a metaphor for how vulnerable to catastrophe the world is deemed to be. WATCH: Here's how the Doomsday Clock changed from 1947 up to last year. The ...